The vomeronasal system is a major source of exteroceptive information to the limbic system. Its functional significance as a system separate from the olfactory system is just now beginning to be understood. The present research uses snakes as experimental subjects for study of the functions of the vomeronasal system because in snakes this system is consistently well developed and usually better developed than the olfactory system. Trailing behavior for food, courtship behavior and aggregative marking behavior are being studied before and after vomeronasal and olfactory system lesions.